The side effects associated with efavirenz affect the central nervous system (CNS) and have not been reported with other anti-HIV drugs.

There are several difficult things about these side effects.

Nearly everyone will get some of these side effects but for most people they will be mild and easy to manage. This means that you may have some strange dreams, or find yourself daydreaming or getting more worried, or you may get more upset than usual.

If you have been told about this before you start treatment, they will be easier to manage and should be less alarming.

Efavirenz CNS side effects can occur after a few hours or after several days and are more common over the first few weeks and months of treatment. They also generally become easier to tolerate as you get used to them.

There is about a 25% chance that these side effects could make it difficult to work as normal until you get used to them.

You should therefore start Efavirenz at the weekend or when you have some time off work, when you are more relaxed and less worried or stressed.

Many of the symptoms described here can also be symptoms of HIV-related diseases that are now seen less frequently such as dementia, TB or cryptococcal meningitis. These can develop slowly over time.

If you experience severe side effects it is easier to switch to a different treatment.

Although most people get used to side effects, a study last year suggested that general side effects may continue at a low level for longer than the first few months.

Severe side effects can lead to or exaggerate clinical depression, including suicidal feelings and clinical paranoia. It is very important therefore that you are aware that such mood swings can be related to Efavirenz and that you are not ‘going mad’.

If you are feeling paranoid and worried about going outside, or have stopped seeing your friends as much, this can also be related to efavirenz side effects.

Why these symptoms are associated with efavirenz is not understood. It is also not possible to predict who will experience more severe symptoms.

Some studies have cautioned against using efavirenz if you are already depressed or have a history of psychiatric illness, but people without such a history have also found symptoms intolerable.

Although you can take efavirenz with or without food, a high fat meal can increase levels by 60%. If you have been taking it with high fat meals this could have increased the side effects.

Taking Efavirenz a couple of hours before you go to sleep, rather than at bedtime, makes it more likely that you will be asleep when the drug levels are at their highest – about four hours after taking efavirenz.

Haloperidol to reduce anxiety and sleeping pills to help with sleep disturbance may also help, although these have not been formally studied.

Some of the symptoms associated with efavirenz are easier to describe than others. The advantage of writing down the effects you experience will let you see whether they are getting less over the first few weeks or months.

Depression and feelings of suicide: A small number of people experience severe side effects have reported feelings of unexplained depression that are out of character, including suicidal thoughts. It is critical to discuss these symptoms with your doctor in order to change to another treatment.

If you are currently taking efavirenz, you may find it easier to talk to a close friend about how you feel and take them with you for support when you visit your doctor.